1. Field of Invention
The present invention relates to a disk order examining system for a dual-controller redundant storage device and method thereof. More particularly, the present invention relates to a system and method for determining the linking orders of disks in a dual-controller redundant storage device.
2. Description of Related Art
Concatenation or Spanning of disks is a popular method for combining multiple physical disk drives into a single virtual disk. Concatenation may be thought of as the reverse of partitioning. Whereas partitioning takes one physical drive and creates two or more logical drives, JBOD uses two or more physical drives to create one logical drive. Concatenation is sometimes used to turn several odd-sized drives into one larger useful drive. For example, JBOD could combine 3 GB, 15 GB, 5.5 GB, and 12 GB drives into a logical drive at 35.5 GB, which is often more useful than the individual drives separately. Though, the controller of JBOD treats each drive as a stand-alone disk and each drive is an independent logical drive, JBOD does not provide data redundancy.
Therefore, if the data storage should be ensured, JBOD is applied in a dual-controller redundant storage device with a master controller and a slave controller of a mutual backing up function. That is, the multiple disks are linked to the master controller and the slave controller in respective orders to form a JBOD. One disk after another of the multiple disks are linked to the master controller with one linking order, and also linked to the slave controller with another linking order. If the linking order of one of the disks to the master controller is not consistent with that to the slave controller, errors occur when data is accessed. Therefore the master controller and the slave controller cannot provide a mutual backing up function under this condition.